I agree that the saying misses the mark a little bit, and the real meaning behind don't roll your own cryto is, to not write some crypto library that you only u

I agree that the saying misses the mark a little bit, and the real meaning behind don't roll your own cryto is, to not write some crypto library that you only use internally and that you are protecting important information with. If you are going to try to create a new crypto library, release it to the world and let them beat the crap out of it, until it is battle hardened then have at it. I think that is the major point, of saying don't roll your own. Is that, someones hack it together in a weekend for logins is going to get broken if someone really wants to get in. But if we did not have people trying out new ideas in cryptography we would have never seen blowfish or ECDSA. I think people should absolutely try writing a crypto library, I don't think they should use it to try to secure anything of importance. I remember back in the BBS days people would actually play a cryto war game where they would write a library, encrypt a message, put it up on the BBS and get people to try to hack it. The message usually contained contact info, with a request to please contact the author and explain how they broke it, so the author could learn from their mistakes.